Hello,

Who has any info about the material used for the hollow 35 front axle ? The AD3 has only 85 kg , I think it is to soft .

regards Udolahr

Normally MH2 for axles.My T 44 axle actually has the MH2 stamped on the side near the spring hole,next to the brinnel test mark.

Do you have any info about the MH2 ?

According to Conway [ GP Bugatti 3 rd edition 2003 page 179] MH2 is a 15% carbon steel from a company called Marine.[EN 36a/or 36b] 60 tons.

The Molsheim T35 frontaxle drawing says AD3 which can easily be heat treated to 100kg/mm2. A frontaxle has to be strong not 'hard'.
Bugwrench

I guess you meant .15% C. MH2 is a normal case hardening steel and was often used by Molsheim for gears. Todays equivalent is 15CrNi6 (Din 1.5919) or 14NiCr14 (Din1.5752). This last one is today often used for replica Bugatti (hollow!) frontaxles.
Bugwrench

0,15% looks much better . I think EN36 has 0,7%. 14NICR14 looks very exotic .In this case better to use 42CrMo4 .What about 20 MnCr5 ? Who is building this hollow axle today ?
Udolahr

"Often?" by whom pray tell.I was under the possibly mistaken belief that only Ivan Dutton had had forging dies made for the proper hollow axle.Tim Dutton tells me that they are having trouble finding a company who can forge these axles now.It would be a shame of they were not made again.The dies cost an absolute fortune.

14NiCr14 (Din 1.5752) is not at all exotic. French Afnor code is 12NC15. SAE/AISI/ASTM code is 3310. Some European suppliers use their own code like ECN35, E200, RAE3, Ovako244 and Thyssen calls it T.E.W.14NiCR14. All suppliers have this steel in stock as this is one of the most popular types of case hardening steel.
20MnCr5 (Din 1.7147) is a case hardening steel in the same category which most suppliers have in stock as well. Good alternative for Bugatti frontaxles.
42CrMo4 is a very popular and very good steel for spindles high tension bolts etc. Has a much higher carbon content and is because of that not suitable for the hollow axle production as the axle ends have to be forged closed after drilling.
Bugwrench

Thank you very much Bugwrench and Lazarus !
I have 20MnCr5 and 42CrMo4 in Stock , this are the 2 most commen steels for me .I belive , I never did touch 14NiCr14 . I need to build this hollow axles and like to use the 20MnCr5 , easy to machine . I was investigating to buy them , but it looks like nobody making them.
Udolahr

Talk to Dutton,he wants to make them again but needs a good company to drop forge the axles.He has all the dies etc.

you mean to forge a straight blank what can be drilled ?

THAT can be drilled yes and also the dies to close up the ends afterwards.

I do not like to use forging to close the ends, there are better ways today . The axle has to be machined all over to look good .

I am curious to hear in what better way you are going to treat the ends after drilling the 28mm hole in order to get sufficient 'meat' to accomodate the 18mm kingpin holes.
Tig Welding?
Why would forging the ends closed interfere with the machining afterwards.
Bugwrench